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A284213
The successive digits of the sequence are the same digits that have a nonprime rank in the sequence.
1
0, 1, 2, 10, 20, 102, 30, 3, 1020, 300, 31, 40, 2030, 50, 4, 3140, 200, 301, 5, 60, 43, 6, 140, 2000, 3015, 7, 600, 436, 11, 402, 70, 100, 3010, 57, 6000, 4360, 1140, 270, 8, 1000, 310, 101, 51, 760, 400, 43601, 1402, 700, 810, 500, 3100, 110, 15, 17, 6040, 80, 9, 436010, 14027, 800, 81, 10500, 13, 1001, 21, 90, 151, 76040, 18
OFFSET
1,3
COMMENTS
The sequence is started with a(1) = 0 and always extended with the smallest integer not yet present and not leading to a contradiction.
EXAMPLE
The first 12 terms are:
0,1,2,10,20,102,30,3,1020,300,31,40
Their successive digits are:
0,1,2,1,0,2,0,1,0,2,3,0,3,1,0,2,0,3,0,0,3,1,4,0
The nonprime rank digits are here (between parentheses):
(0),1,2,(1),0,(2),0,(1),(0),(2),3,(0),3,(1),(0),(2),0,(3),0,(0),(3),(1),4,(0),
Erasing the digits not in the parentheses:
(0),.,.,(1),.,(2),.,(1),(0),(2),.,(0),.,(1),(0),(2),.,(3),.,(0),(3),(1),.,(0),
The surviving digits are:
0,1,2,1,0,2,0,1,0,2,3,0,3,1,0,...
Those are indeed the digits of the starting sequence.
CROSSREFS
Sequence in context: A294493 A261660 A004643 * A156818 A037422 A136735
KEYWORD
nonn,base
AUTHOR
STATUS
approved